15 W 2-channel BTL AF Power Amplifier
for Car Stereos
Overview
The LA4705 is a BTL two-channel power IC for car audio and
radio-cassette players developed in pursuit of excellent sound
quality. Low-region frequency characteristics have been
improved through the use of a new NF capacitorless circuit,
and crosstalk which causes ``muddy'' sound has been reduced
by improving both circuit and pattern layout. As a result, the
LA4705 provides powerful bass and clear treble. In addition,
the LA4705 features on-chip protectors and standby switch.
Features
.
High power: supports total output of 25 W + 25 W
(V
CC
= 14.4 V, THD = 30%, R
L
= 4
)
.
Less pop noise
.
Designed for excellent sound quality
(f
L
< 10 Hz, f
H
= 130 kHz)
.
Any on time settable by external capacitor
.
Standby switch circuit on chip (microprocessor supported)
.
Various protectors on chip
(output-to-ground short/output-to-V
CC
short/
load short/overvoltage/thermal shutdown circuit)
.
NF capacitorless
.
Supports R
L
= 2
Package Dimensions
unit: mm
3109-SIP18H
[LA4705]
SANYO : SIP18H
Specifications
Maximum Ratings
at Ta = 25C
Parameter
Symbol
Conditions
Ratings
Unit
Maximum supply voltage
V
CC
max 1
No signal, t = 60 s
24
V
V
CC
max 2
With signal
18
V
Surge supply voltage
V
CC
surge
t
%
0.2 s, single giant pulse
50
V
Allowable power dissipation
Pd max
Arbitrarily large heat sink
37.5
W
Operating temperature
Topr
35 to +85
C
Storage temperature
Tstg
40 to +150
C
* Set V
CC
, R
L
in a range that does not exceed Pd max = 37.5 W
Ordering number: EN3848D
Monolithic Linear IC
LA4705
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
D3096HA(II)/12693TS/4152TS No.3848-1/8
Operating Conditions
at Ta = 25C
Parameter
Symbol
Conditions
Ratings
Unit
Recommended supply voltage
V
CC
13.2
V
Operating voltage range
V
CC
op
Range where Pd max is not exceeded
9 to 18
V
Recommended load resistance
R
L
4
Operating Characteristics
at Ta = 25C, V
CC
= 13.2 V, R
L
= 4
, f = 1 kHz, Rg = 600
Parameter
Symbol
Conditions
min
typ
max
Unit
Quiescent current
I
CCO
80
115
250
mA
Standby current
Ist
10
60
A
Voltage gain
VG
38
40
42
dB
Total harmonic distortion
THD
P
O
= 1 W
0.1
0.4
%
Output power
P
O
1
THD = 10%
11
15
W
P
O
2
THD = 10%, V
CC
= 14.4 V
18
W
P
O
3
THD = 10%, R
L
= 2
16
W
Output offset voltage
V
N
offset
Rg = 0
300
+300
mV
Output noise voltage
V
NO
Rg = 0, B.P.F. = 20 Hz to 20 kHz
0.1
0.5 mVrms
Ripple rejection ratio
SVRR
Rg = 0, f
R
= 100 Hz, V
R
= 0 dBm
40
50
dB
Channel separation
CHsep
Rg = 10 k
, V
O
= 0 dBm
50
60
dB
Input resistance
r
i
21
30
39
k
Standby pin applied voltage
Vst
Amp on, applied through 10 k
2.5
V
CC
V
Allowable
power
dissipation,
Pd
max
W
Arbitrarily large heat sink
Ambient temperature, Ta C
Heat
sink
thermal
resistance,
f
C/W
Al heat sink, t = 1.5 mm
Tightening torque 39 N
c
cm
With silicone grease applied
Heat sink area, S
f
cm
2
Pd max Ta
f
S
f
LA4705
No.3848 -2/8
Features and Usage Notes
.
Pin 5 is the standby switch pin. The amplifier is turned on by applying approximately 2 V or more to this pin through an
external resistor (R1). The current flowing into pin 5 is 500 A or less.
.
Pin 6 is the mute pin. The amplifier on time can be set as desired through C3. By grounding pin 6, the amplifier can implement
mute operation. In this case, the recovery time depends on C3.
.
In order to prevent damage or degradation which may be caused by abnormally heated IC, the LA4705 has a thermal shutdown
protector. Accordingly, in the case of inadequate heat dissipation, the thermal shutdown protector will operate to control the
output gradually into attenuation.
.
Also be fully careful of handling other protectors built in the LA4705.
Sample Application Circuit
Unit (resistance:
, capacitance: F)
LA4705
No.3848 -3/8
Sample Print Pattern
Description of External Components
C1, C4
Input capacitors
2.2 F is recommended. f
L
can be varied by C1, C4 capacitances to adjust the
bass range.
C2
Decoupling capacitor
(ripple filter)
C3
Amplifier on time setting
capacitor
Approximately 0.6 to 0.7 second for 33 F. Since the on time is proportional to
this capacitance, it can be set as desired by varying this capacitance. The
amplifier can implement mute operation by setting C3 to GND potential.
C5
Power supply capacitor
C6, C7, C8, C9
Oscillation blocking capacitors
Use polyester film capacitors (Mylar capacitors) with good temperature
characteristics. (R2, R3, R4, and R5 used jointly.) Since stability may be
affected slightly by the pattern layout, etc., 0.1 F or more is recommended.
R1
Standby switch current limiting
resistor
10 k
is recommended. This resistor cannot be removed.
Copper foil area 90
105 mm
2
LA4705
No.3848 -4/8
Output
power
,
P
O
W
Supply voltage, V
CC
V
Output
power
,
P
O
W
Input level, V
IN
Vrms
Output
power
,
P
O
W
Supply voltage, V
CC
V
T
otal
harmonic
distortion,
THD
%
Output power, P
O
W
T
otal
harmonic
distortion,
THD
%
Output power, P
O
W
T
otal
harmonic
distortion,
THD
%
Output power, P
O
W
T
otal
harmonic
distortion,
THD
%
Input frequency, f Hz
Response
d
B
Input frequency, f Hz
0 dBm = VG 40 dB
P
O
V
IN
P
O
V
CC
P
O
V
CC
THD P
O
THD P
O
THD P
O
THD f
f Response
LA4705
No.3848 -5/8
Channel
separation,
CHsep
d
B
Input frequency, f Hz
Output
power
,
P
O
W
Input frequency, f Hz
Ripple
rejection
ratio,
SVRR
d
B
Supply voltage, V
CC
V
SVRR V
CCR
V
NO
Rg
Ripple
rejection
ratio,
SVRR
d
B
Ripple frequency, f Hz
Package allowed power dissipation
Ripple
rejection
ratio,
SVRR
d
B
Power supply ripple voltage, V
CCR
Vrms
Pd, I
CC
P
O
Output
noise
voltage,
V
NO
m
V
rms
Input resistance, Rg
Pd, I
CC
P
O
Power
dissipation,
Pd
W
Output power, P
O
W
Power
dissipation,
Pd
W
Output power, P
O
W
CH sep f
P
O
f
SVRR V
CC
SVRR f
Current
drain,
I
CC
A
Current
drain,
I
CC
A
LA4705
No.3848 -6/8
Power
dissipation,
Pd
W
Output power, P
O
W
Pd, I
CC
P
O
Quiescent
current,
I
CCO
m
A
Supply voltage, V
CC
V
Output
pin
voltage,
V
N
V
Supply voltage, V
CC
V
Quiescent
current,
I
CCO
m
A
Ambient temperature, Ta C
Output
power
,
P
O
W
Ambient temperature, Ta C
V
N
V
CC
T
otal
harmonic
distortion,
THD
%
Ambient temperature, Ta C
I
CCO
Ta
THD Ta
Amp
ON
time
s
C4 F
P
O
Ta
Output
pin
voltage,
V
N
V
Standby pin applied voltage, V
ST
V
Amp ON time C4
V
N
V
ST
Unit (resistance:
)
I
CCO
V
CC
Current
drain,
I
CC
A
No load
No load
LA4705
No.3848 -7/8
No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment,
nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or
indirectly cause injury, death or property loss.
Anyone purchasing any products described or contained herein for an above-mentioned use shall:
1
Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors
and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and
expenses associated with such use:
2
Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO
ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume
production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use
or any infringements of intellectual property rights or other rights of third parties.
This catalog provides information as of December, 1996. Specifications and information herein are subject to change without notice.
BTL output DC locus
AC Level
Locus when ON
BTL output DC locus
AC Level
Locus when OFF
LA4705
No.3848 -8/8
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